JP2001352656A - Joint for power cable using cold shrinking insulator, and its assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a construction which is small-sized and light, and moreover displays an excellent insulation performance over a long period of time. SOLUTION: Inside a cold shrinking insulator 11, a conductor connector element 12 is wrapped, buried, and supported. Connecting terminals 18, 18, fixed to the ends of cable conductors which constitute individual power cables 1, 1 to be connected, are inserted into and connected to the joints of the connector element 12. It is unnecessary to cause the insulator 11 to take refuse near the center of one 1 of the power cables, on the occasion of connecting work, and it becomes possible to reduce size and weight. Also proper insulation performance can be exhibited over a long period of time, since displacement of the insulator 11 in the axial direction of the power cables 1, 1 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a power cable connecting portion using a cold-shrinkable insulator and a method for assembling the same, for example, a cable conductor constituting a high-voltage power cable such as a cross-linked polyethylene insulated power cable (CV cable). It is used to form a straight connection portion or a Y-branch connection portion for connecting the end portions.

[0002]

2. Description of the Related Art A pair of power cables is constituted by a room-temperature shrinkable tube (pre-mold sleeve) made of rubber, which is an elastic material, as a structure capable of relatively easily connecting the ends of a high-voltage power cable. A structure for covering a connection portion between cable conductors is known. FIG. 9 shows an example of a straight-line connection portion of a power cable using such a cold-shrinkable tube.

[0003] A pair of power cables 1 to be connected to each other,
1 comprises a cable conductor 2 covered with a cable insulator 3. Portions of the pair of power cables 1 and 1 protruding from the cable insulator 3 at ends of the cable conductors 2 are connected by a connection sleeve 4 which is a kind of conductor connector. The periphery of the connection sleeve 4 is covered by a cold shrink tube 5 which is a cold shrinkable insulator. The cold-shrinkable tube 5 is made of rubber, which is a kind of a polymer material, and is formed in a cylindrical shape. A high-voltage electrode is provided on an inner peripheral surface portion of the insulating cylindrical portion 6 made of rubber having an insulating property at an intermediate position in the axial direction. Embedded therein is a semi-conductive rubber internal electrode 7. or,
The outer peripheral surface of the insulating cylinder 6 is covered with a semi-conductive rubber external electrode 8 which is a low-voltage electrode.

[0004] The cold shrinkable tube 5 as described above is provided with the above 1
Prior to connecting the ends of the cable conductors 2 of the pair of power cables 1 and 1 with the connection sleeve 4, one of the power cables 1 is inserted in advance. The cold shrink tube 5 is provided on the inner diameter side of the cold shrink tube 5.
A cylindrical holding sleeve 9 (see FIG. 10 to be described later) for holding the diametrically expanded state is previously inserted at a factory or site. Therefore, the cold shrinkable tube 5 is in a state where elasticity in the diameter reducing direction is given. After the ends of the cable conductors 2 of the pair of power cables 1 and 1 are connected to each other by a connection sleeve 4, the cold-shrinkable tube 5 is connected to the cable insulator forming the pair of power cables 1 and 1. After moving the holding sleeve to the cold-shrinkable tube 5
From the inner diameter side.

[0005] FIG.
1 shows an example of a holding sleeve 9 for holding the sleeve in an expanded state. The holding sleeve 9 is like a wire wound in a spiral shape, and is inserted through the cold shrink tube 5 with the cold shrink tube 5 expanded in diameter. At the time of assembling the straight connection portion, the end portion 10 of the wire is pulled out through the inside of the holding sleeve 9 as shown in FIG. As a result, the diameter of the cold shrinkable tube 5 is reduced from one end in the axial direction (the left end in FIG. 10). As the holding sleeve 9 is withdrawn from the inner diameter side of the cold shrink tube 5 in this manner, the cold shrink tube 5 is reduced in diameter by its own elasticity. The power cables 1 are elastically brought into contact with the outer peripheral surfaces of the ends of the cable insulators 3 constituting the power cables 1.

[0006]

In the case of the straight-line connecting portion shown in FIG. 9 which is a kind of the connecting portion for the power cable using the cold-shrinkable insulator, the axial dimension of the connecting portion as a whole increases. In addition, if it is installed in a place where the temperature change is remarkable, the insulation performance may be deteriorated after a long period of time. This will be described below.

First, the point that the axial dimension increases will be described. Before the cold-shrink tube 5 and the holding sleeve 9 connect one end of the cable conductors 2, 2 constituting the pair of power cables 1, 1 to be connected to each other with the connection sleeve 4, one of them is connected. Needs to be externally fitted to the power cable 1. When the diameter of the connection sleeve 4 is reduced with a die so as to connect the ends of the pair of cable conductors 2 and 2, the cold shrink tube 5 is used.
And the holding sleeve 9 must be retracted to the central portion of the one power cable 1. Therefore, the outer diameter of the one power cable 1 must be smaller than the inner diameter of the holding sleeve 9 up to the central portion where the cold shrink tube 5 and the holding sleeve 9 are to be retreated.

For this purpose, conventionally, a shielding layer and an anticorrosion layer provided around the cable insulator 3 constituting the one power cable 1 are peeled off to the center portion of the power cable, and the cold shrink tube 5 is formed. In addition, a place where the holding sleeve 9 is to be retracted is secured. The portion where the shielding layer, the anticorrosion layer, and the like have been peeled off in this way must be newly covered with the shielding layer, the anticorrosion layer, and the like after the cold shrink tube 5 is wrapped between the pair of power cables 1 and 1. Must. As described above, since the outer diameter of the shielding layer and the anticorrosion layer newly provided by the on-site work is larger than the outer diameter of the shielding layer and the anticorrosion layer originally provided in the one power cable 1, as described above, The dimension in the axial direction of the entire connection portion increases. Further, when the moving distance of the cold shrink tube 5 and the holding sleeve 9 with respect to the power cable 1 becomes longer during the connection work, foreign matters can be taken into the installation portion of the connection sleeve 4 which requires a high degree of insulation. It is not preferable because the property becomes high.

On the other hand, the holding sleeve 9 having a large inner diameter is used, and the holding sleeve 9 and the cold shrinkable tube 5 externally fitted to the holding sleeve 9 are connected to a portion provided with the shielding layer and the anticorrosion layer. It is conceivable to be able to move to the surrounding area. However, when such a method is adopted, the diameter expansion ratio (diameter in the expanded state / diameter in the free state) of the cold shrink tube 5 must be increased. Increasing the diameter expansion ratio not only complicates the work of externally fitting the cold shrink tube 5 to the holding sleeve 9 but also applies an excessive force to the rubber material constituting the cold shrink tube 5. This is not preferable because it causes the durability of the cold shrink tube 5 to deteriorate.

Next, the possibility that the insulation performance deteriorates after a long period of time will be described. In the case of the conventional structure shown in FIG. 9, a pair of power cables 1, 1 and a connection sleeve 4
The room-temperature shrinkable tube 5 is not mechanically unevenly engaged or chemically bonded. The power cables 1, 1 and the connection sleeve 4 are prevented from slipping from the cold shrink tube 5 by the inner peripheral surface of the cold shrink tube 5 and the outer periphery of the cable insulators 3 constituting the power cables 1, 1. Only frictional force acting between surfaces is used.

On the other hand, since the cold shrink tube 5 and the cable insulators 3 are made of different materials, the amounts of thermal expansion and shrinkage due to temperature changes are slightly different.
For this reason, when the straight-line connecting portion as shown in FIG. 9 is installed in a place where the temperature change is remarkable, the pair of power cables 1 and 1 and the connecting sleeve 4 are used with long-term use.
The mounting position of the cold shrink tube 5 may shift. Then, if the displacement of the mounting position becomes large, the insulation performance of the above-mentioned straight-line connecting portion is deteriorated. The power cable connecting portion using the cold-shrinkable insulator and the method of assembling the same according to the present invention have been invented in order to eliminate any such disadvantages.

[0012]

According to the present invention, there is provided a connection part for a power cable using a cold-shrinkable insulator according to the present invention and a method for assembling the same. The portions are the ends of the cable conductors constituting at least one pair of power cables to be connected to each other, and the portions protruding from the cable insulators constituting each of the power cables are connected to the room temperature, similarly to the conventional structure described above. Inside the shrinkable insulator, they are connected to each other via a conductor connector, and the inner circumferential surface of the end of the cold shrinkable insulator is entirely formed around the outer circumferential end of the cable insulator constituting each of the power cables. Abutting over a period of time.

In particular, in the power cable connecting portion using the cold-shrinkable insulator of the present invention, the conductor connector has a number of connecting portions corresponding to the number of power cables to be connected. And is embedded and supported inside the cold shrinkable insulator. An insertion hole is provided in a part of the cold-shrinkable insulator that is aligned with each of the above-mentioned connecting portions, so that each of these connecting portions and the outer surface of this cold-shrinkable insulator can pass through. Further, a connection terminal for connecting each of the cable conductors to the conductor connector is fixed to an end of each of the cable conductors by being inserted into each of the connection portions.

Preferably, at least a portion of each of the insertion holes, which is close to each of the connection portions, is provided with a force for elastically expanding the inner diameter of the insertion hole. Is formed by cylindrically arranging elements having a bending rigidity that is not substantially bent, and by embedding and supporting a support cylinder capable of expanding and contracting the diameter in an elastic material constituting the cold-shrinkable insulator. Provide.

According to a third aspect of the present invention, there is provided a method for assembling a connection portion for a power cable using a cold-shrinkable insulator, wherein the cold-shrinkable insulator has an inner end provided with at least a distal end located at a leading edge. The end of the power cable to be connected to the inside of the enlarged diameter tube is inserted in a state in which the inner diameter of the insertion hole is expanded by pushing a tubular enlarged diameter tube which is inclined in a direction in which the outer diameter becomes smaller as it goes. Then, a connection terminal previously fixed to an end of a cable conductor constituting the power cable is inserted into a connection portion of a conductor connector embedded in the cold shrinkable insulator, and the conductor connector and the cable are inserted. The conductor and the conductor are connected via the connection terminal. afterwards,
Withdrawing the diameter-expanding tube from the inside of the insertion hole, elastically shrinking the insertion hole portion with a part of the cold-shrinkable insulator, and connecting the inner peripheral surface of the insertion hole to the cable insulator constituting the power cable. Close to the outer peripheral surface of the end.

[0016]

According to the power cable connecting portion using the cold-shrinkable insulator of the present invention and the assembling method thereof, the axial dimension of the entire connecting portion can be reduced,
Even if it is installed for a long time in a place where temperature changes are remarkable, it is possible to prevent the insulation performance from deteriorating.

That is, the ends of the cable conductors constituting each power cable to be connected and the conductor connector can be connected by inserting the cable conductor into an insertion hole provided in the cold-shrinkable insulator. It is not necessary to retract this cold-shrinkable insulator toward the center of any of the power cables during the connection operation. Therefore, the shielding layer and the anticorrosion layer of any of the power cables to be connected to each other need not be provided at the center of the cold-shrinkable insulator without increasing the diameter expansion rate of the cold-shrinkable insulator. It is no longer necessary to peel off to the portion, and the axial dimension of the entire power cable connecting portion can be reduced.

The conductor connector for connecting the ends of the cable conductors constituting the power cables to be connected to each other is embedded in the cold-shrinkable insulator. There is no displacement with respect to the body. For this reason, this cold-shrinkable insulator does not displace with respect to each of the power cables, and as described above, even when the insulator is installed for a long time in a place where the temperature change is remarkable, it is possible to prevent the insulation performance from deteriorating. .

[0019]

1 to 6 show a first embodiment of the present invention. This example shows a case where the present invention is applied to a linear connecting portion for connecting ends of a pair of power cables 1 and 1. For this reason, in the case of the present example, the ends of the cable conductors 2, 2 forming the pair of power cables 1, 1 protrude from the cable insulators 3, 3 forming the respective power cables 1, 1. The connected portions are connected to each other via a conductor connector 12 inside a cold-shrinkable insulator 11 as shown in FIG. Then, the inner peripheral surface of the end portion of the cold-shrinkable insulator 11 is brought into contact with the outer peripheral surface of the end portion of the cable insulators 3 constituting the power cables 1 over the entire circumference.

The conductor connector 12 is made of a metal having a low electric resistance, such as copper, aluminum, or an alloy thereof, and is connected to both end faces in the axial direction (left and right directions in FIGS. 1 and 2). (Not shown). Each of these connection portions has a circular hole shape opened at both axial end surfaces of the conductor connector 12, and a metal connection sleeve is provided on each inner peripheral surface. Regarding the structure of such a connection portion, various structures that have been widely known can be adopted, and therefore illustration and detailed description are omitted. The conductor connector 12 having the pair of connection portions is provided with a center hole 13 of the conductor connector 12 inside the middle portion of the cold-shrinkable insulator 11 in the axial direction.
Are embedded and supported in a state where they are partitioned at a central portion in the axial direction.

The above-mentioned cold-shrinkable insulator 11 is the same as that shown in FIG.
Similarly to the cold-shrinkable tube 5 constituting the conventional structure shown in FIG. 1, the cylindrical insulating portion 1 is made of rubber, which is a kind of polymer material, and has a cylindrical shape.
A semi-conductive rubber internal electrode 7a is embedded in the inner peripheral surface portion at the axial intermediate position of
4 is made of a semiconductive rubber external electrode 8a.
Covered by. The conductor connector 12 has its outer diameter portion embedded in the axially intermediate portion of the inner electrode 7a near the inner diameter when the internal electrode 7a is formed.
Therefore, the conductor connector 12 is connected to the cold-shrinkable insulator 1.
1 is supported and fixed non-displaceably inside the intermediate portion of the first member.

In this manner, both ends in the axial direction of the conductor connector 12 supported and fixed to the inner central portion of the cold shrinkable body 11 are:
The axially opposite end faces of the cold shrinkable body 11 correspond to the center hole 1 described above.
3 communicate with each other. That is, in the case of this example,
Out of the center hole 13, portions near both ends except for a central portion that embeds and supports the conductor connector 12 allow the connection portions to pass through the outer surfaces (both axial end surfaces) of the cold-shrinkable insulator 11. These are insertion holes 15 and 15. Each of these insertion holes 1
The inner electrode 7a is provided at the inner end portion of the inner peripheral surface of each of the inner and outer conductors 5 and 15 near the conductor connector 12, the insulating portion 14 is provided at an intermediate portion, and the outer electrode portion is provided at the outer end portion near both ends of the opening. 8a
However, each is exposed.

A support cylinder 16 as shown in FIG. 3 is embedded and supported near the axial ends of the internal electrode 7a and inside the portions forming the inner end portions of the insertion holes 15, 15. ing. The support tube 16 is formed by arranging a plurality of elements 17, 17 each formed in a partially cylindrical shape as shown in FIG. 4 in a cylindrical shape, and is capable of expanding and contracting in diameter. Each of these elements 17, 17 is made of metal or synthetic resin, etc.
It is made of a material having greater rigidity than the rubber constituting the internal electrode 7a, and each has a bending rigidity such that it is not substantially bent by a force for elastically expanding the inner diameter of the insertion holes 15, 15. Having. If necessary, the ends of the support cylinder 16 near the conductor connector 12 are bundled by a locking ring, and the respective elements 17, 17
However, it does not disperse during the embedding work in the internal electrode 7a. If the internal electrode 7a may be deformed when the diameter is increased, the support cylinder 16 may be omitted.

On the other hand, connection terminals 18, 18 are connected and fixed to the ends of the respective cable conductors 2, 2 constituting the pair of power cables 1, 1 to be connected. That is, at the end of each of the cable conductors 2 and 2 exposed from the end of each of the cable insulators 3, the connection terminal 1 is attached.
The compression terminal portions 19, 19 provided on the base half portions (the opposite half portions) of 8, 8 are fitted to the outside, and these compression terminal portions 19, 19
The diameter of 19 is reduced so that the inner peripheral surfaces of the compression terminal portions 19 and 19 are in close contact with the outer peripheral surfaces of the ends of the cable conductors 2 and 2. Connection terminal portions (not shown) are respectively provided at the first half portions (half portions on opposite sides) of the connection terminals 18, 18 fixedly connected to the end portions of the cable conductors 2, 2 in this manner. ). Each of these connection terminal portions is inserted into each connection portion of the conductor connector 12 to connect the connection terminals 18 to the conductor connector 12. In addition, as for the structure of such a connection terminal portion, similarly to the structure of each of the above-described connection portions, various conventionally known structures can be adopted, and thus illustration and detailed description are omitted.

As described above, the pair of power cables 1, 1
In a state where the ends of the cable conductors 2 and 2 constituting the above are connected via the conductor connector 12 and the connection terminals 18 and 18, the inner peripheral surfaces of both ends of the cold-shrinkable insulator 11 are removed. Each of the power cables 1 is in contact with an outer peripheral surface of an end portion of the cable insulator 3 around the entire circumference. As described above, since the cold-shrinkable insulator 11 is made of elastic rubber, the surface pressure of the contact portion between the two peripheral surfaces is sufficiently ensured. Therefore, the installation portion of the conductor connector 12 and the connection terminals 18, 18 is isolated from the outside, and the insulation of the connection portion between the pair of power cables 1, 1 can be sufficiently ensured.

The power cable connecting portion using the above-mentioned cold-shrinkable insulator is assembled as follows. The entire structure of the cold shrinkable insulator 11 in which the conductor connector 12 is embedded and supported is as shown in FIG. 2, but before the assembly work, both ends of the cold shrinkable insulator 11 are assembled. As shown in FIG. 5, the inner diameter is expanded by the expanded tubes 20 and 20. Each of these enlarged diameter tubes 2
0 and 20 are a pair of tube elements 2 as shown in FIG.
1, 21 are superimposed in the middle, and the cylindrical portion 22
And a tapered tapered portion 23 which is inclined in a direction in which the diameter becomes smaller as the distance from the cylindrical portion 22 increases. The inner diameter of the distal end opening of the tapered tapered portion 23 is equal to or larger than the outer diameter of each of the cable insulators 3, and passes through the distal end opening through the connection terminals 18, 18 and these cable insulators 3, 3. It is free. In addition, concave and convex portions that engage with each other are provided on both circumferential edges of the tube elements 21, 21, and when the two tube elements 21, 21 are overlapped, the both end edges do not shift and move. Like

Prior to the assembling operation, each of the expanded tubes 20 and 20 is pushed into the insertion holes 15 and 15 of the cold-shrinkable insulator 11 at a factory or a work site, as shown in FIG. First, the inside diameters of these two insertion holes 15 are increased. In this way, the tapered portions 23, 23 of the expanded tubes 20, 20, with the expanded tubes 20, 20, pushed into the insertion holes 15, 15, respectively.
Are located inside both ends of the internal electrode 7a. The leading edge of each of the tapered portions 23 is connected to the conductor connector 1.
Although it is not possible to abut against the end face of No. 2, as described above, a support cylinder 16 made of elements 17 having sufficient rigidity and having a diameter that can be enlarged and reduced is provided inside the internal electrode 7 a. I have. For this reason, even if gaps 24 exist between the tip edges of the tapered portions 23 and the end faces of the conductor connector 12 as shown in FIG. , Including the portions surrounding these gaps 24, 24 can be made sufficiently large. That is, by providing the support tube 16, the entire internal electrode 7 a is pushed and expanded into a conical cylindrical shape with the insertion of the respective enlarged diameter tubes 20, 20, and the inner diameter of the portion surrounding the gaps 24, 24 is also increased. The outer diameter of each of the connection terminals 18, 18 can be made larger than the outer diameter.

As described above, each of the above-mentioned enlarged tubes 20, 20
By inserting the power cables 1, the ends of the power cables 1, 1 to be connected are inserted into the enlarged diameter tubes 20, 20 with the inner diameters of the insertion holes 15, 15 expanded.
The connection terminals 18, 1, which are fixed in advance to the ends of the cable conductors 2, 2 constituting these power cables 1, 1, respectively.
8 is inserted into the connection portion of the conductor connector 12 embedded in the cold-shrinkable insulator 11. As a result, the conductor connector 12 and the cable conductors 2 and 2 are coupled via the connection terminals 18 and 18. Thereafter, the respective enlarged tubes 20 are pulled out from the inside of the respective insertion holes 15. As a result, the diameters of both ends of the cold-shrinkable insulator 11 are elastically reduced, and the inner peripheral surfaces of the insertion holes 15 are formed of the cable insulators 3 constituting the power cables 1. Close contact with the outer peripheral surface of the end. After being pulled out from each of the insertion holes 15, 15, the respective enlarged tubes 20, 20 are separated into tube elements 21, 21 and removed from around the power cables 1, 1. Then, it is reused for the assembling work of another power cable connecting portion. In order to facilitate the work of removing the expanded tubes 20, 20 without removing the anticorrosion layer and the like of the power cables 1, 1, each of the expanded tubes 20, 20 is pivoted. It may be divided into a plurality of elements in the direction. In this case, it is preferable to connect the elements adjacent in the axial direction to each other in a detachable manner.

As the expanded tube used for the assembling work, in addition to the tube having the above-described shape, as shown in FIG. 7, tube elements 21a, 21a each having a semi-conical shape are combined in the middle. Also, a conical cylindrical expanded tube 20
a can also be used. Furthermore, although illustration is omitted,
As shown in FIG. 10 described above, an expanded tube having a structure in which a wire is spirally wound and having a shape as shown in FIG. 6 or 7 can also be used. In any case, the material of the expanded tube is not limited. Further, the ends of the cable insulators 3, 3 constituting the power cables 1, 1 are cut off into an appropriate shape such as a tapered shape, and the enlarged tubes 20, 20 are inserted into the insertion holes 15, 15, respectively. In the state of being pulled out from the cable, the inner peripheral surface of the internal electrode 7a can be closer to the outer peripheral surfaces of the cable conductors 2 and 2 than the state shown in FIG. In this case, the outer diameter of the power cable connecting portion using the cold-shrinkable insulator can be reduced, and the power cable connecting portion can be reduced in size and weight.

According to the power cable connecting portion using the cold shrinkable insulator of the present invention constructed as described above and assembled as described above, the axial dimension of the entire connecting portion can be shortened. That is, the ends of the cable conductors 2, 2 constituting each of the power cables 1, 1 to be connected, and the conductor connector 12 embedded in the cold-shrinkable insulator 11 are connected to the cable conductors 2, 2. Can be connected by inserting them into insertion holes 15 provided in the cold-shrinkable insulator 11. Therefore, it is not necessary to retract the cold shrinkable insulator 11 near the center of any of the power cables 1 during the connection work. Therefore, the shielding layer and the anticorrosion layer of any of the power cables 1 and 1 to be connected to each other need not be provided without increasing the diameter expansion rate of the cold shrinkable insulator 11. It is not necessary to peel off to the length of 11. Therefore, the length of the portion where the shielding layer and the anticorrosion layer are to be provided later is shortened, the axial dimension of the entire power cable connection portion can be reduced, and the installation work in a narrow space such as a manhole can be easily performed. Become. In addition, since the room-temperature shrinkable insulator 11 is not moved to a portion near the center of any of the power cables 1 and 1, there is a danger that foreign matter that may lead to insulation failure may be taken into the inside of the power cable connection portion. Can be reduced.

Such an effect is achieved by the ordinary power cable 1,
Although a sufficient connection can be obtained even when one power supply is connected to one another, it becomes more remarkable when a power cable called a triplex type in which three power cables are twisted is connected. That is, when connecting the ends of the three power cables constituting the triplex type cable, it is necessary to loosen these three power cables. As in the case of the conventional structure shown in FIG. 9 described above, if it is necessary to fit the cold shrink tube 5 outside the center portion of any of the power cables 1, the amount that must be loosened increases. According to this, this amount can be reduced. When connecting the triplex type cable by the structure and method of the present invention, three cold-shrinkable insulators used for the connection may be bundled together. According to this configuration, the connection work of the three power cables constituting the triplex type cable is collectively performed to improve the efficiency of the connection work, and further, the shielding processing of the protective copper pipe and the like is collectively performed. As a result, the overall size of the power cable connection can be reduced.

The conductor connector 12 for connecting the ends of the cable conductors 2 and 2 constituting the pair of power cables 1 and 1 to be connected to each other is formed of the cold shrinkable insulator 1.
1 and is not displaced with respect to the cold-shrinkable insulator 11. The conductor connector 12 and the cable conductors 2 are connected to each other via the connection terminals 18. Therefore, the cold shrinkable insulator 11 is not displaced with respect to the power cables 1, 1. For this reason, as described above, even when the power cable connecting portion using the cold shrinkable insulator is installed for a long time in a place where the temperature change is remarkable, the cold shrinkable insulator 11 can be used.
And the positional relationship between the power cables 1 and 1 is maintained as normal. As a result, it is possible to prevent the insulation performance of the power cable connecting portion using the cold shrinkable insulator from deteriorating.

FIG. 8 shows a second embodiment of the present invention.
An example is shown. This example shows a case where the present invention is applied to a Y-branch connection portion that connects an end of one power cable 1 and an end of two power cables 1 and 1.
For this reason, in the case of the present example, one portion (the left surface in FIG. 8) of the conductor connector 12a and the other portion (the right surface in FIG. 8) of the conductor connector 12a embedded in the cold-shrinkable insulator 11a Are provided with connection parts (not shown) at a total of three places. The openings of these connection portions and the outer surface of the cold-shrinkable insulator 11a are connected to each other by the insertion holes 15a, 15a. The present invention can be configured similarly to the case of the above-described linear connection portion of the first example even with the structure of the Y branch portion. The features that characterize the present invention are the same as those in the first example. Therefore, for the points other than those described above, the same reference numerals are given to the same parts, and duplicate descriptions are omitted.

[0034]

Since the present invention is constructed and operated as described above, it is small and lightweight, and has a normal temperature shrinkable insulator capable of exhibiting good insulation performance over a long period of time. Part can be realized. In addition, the present invention can be applied to the Y-branch connection portion, which has conventionally been difficult to use the cold shrinkable insulator, and the cost required for installing the Y-branch connection portion can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing only a normal-temperature shrinkable insulator.

FIG. 3 is a perspective view of a support cylinder embedded in an internal semiconductive layer.

FIG. 4 is a perspective view of an element constituting the support cylinder.

FIG. 5 is a cross-sectional view showing a state where both ends of a cold-shrinkable insulator are expanded in diameter in order to perform a connection operation.

FIG. 6 is a perspective view showing a first example of an enlarged-diameter tube.

FIG. 7 is a perspective view showing the second example.

FIG. 8 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 9 is a cross-sectional view showing an example of a power cable connecting portion using a conventionally known cold-shrinkable insulator.

10A and 10B show a state for forming an example of this conventional structure, in which FIG. 10A is a cross-sectional view showing a state before the cable is externally fitted, and FIG. Sectional drawing which shows the state in the middle of pulling out a sleeve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power cable 2 Cable conductor 3 Cable insulator 4 Connection sleeve 5 Cold shrinkable tube 6 Insulating cylinder part 7, 7a Internal electrode 8, 8a External electrode 9 Holding sleeve 10 End part 11, 11a Cold shrinkable insulator 12, 12a Conductor connector 13 Center hole 14 Insulation part 15, 15a Insertion hole 16 Support tube 17 Element 18 Connection terminal 19 Compression terminal part 20, 20a Large diameter tube 21, 21a Tube element 22 Cylindrical part 23 Tapered part 24 Gap

Claims (4)

[Claims] 1. An end portion of a cable conductor constituting at least one pair of power cables to be connected to each other, a portion protruding from a cable insulator constituting each of these power cables is connected to the inside of a cold-shrinkable insulator. Then, while being connected to each other via a conductor connector, the inner peripheral surface of the end portion of the cold-shrinkable insulator is brought into contact with the outer peripheral surface of the end portion of the cable insulator constituting each power cable over the entire circumference. In the connection part for the power cable using the cold-shrinkable insulator consisting of
The conductor connector has a number of connection portions corresponding to the number of power cables to be connected, is embedded and supported inside the cold shrinkable insulator, and a part of the cold shrinkable insulator. An insertion hole through which each of the connection portions and the outer surface of the cold-shrinkable insulator is provided is provided at a portion corresponding to each of the connection portions, and an end of each of the cable conductors is provided with the connection portion. A connection terminal for connecting each of the cable conductors to the conductor connector by being inserted into the power cable connection portion, wherein the connection portion for a power cable using a cold-shrinkable insulator. 2. An element having a bending rigidity such that it is not substantially bent by a force for elastically expanding the inner diameter of the insertion hole, at a portion of at least a part of each insertion hole which is close to each connection portion. 2. The cold-shrinkable insulator according to claim 1, wherein the support cylinder, which is arranged in a cylindrical shape and whose diameter is freely expandable and contractable, is provided by being embedded and supported in an elastic material constituting the cold-shrinkable insulator. Connection for power cable using. 3. An assembling method for assembling a connection portion for a power cable using the cold-shrinkable insulator according to claim 1, wherein the cold-shrinkable insulator is provided inside an insertion hole of the cold-shrinkable insulator. With the inner diameter of the insertion hole expanded by pushing the tubular enlarged tube, the end of the power cable to be connected to the inside of the enlarged tube is inserted, and the end of the cable conductor constituting the power cable is inserted. The connection terminal previously fixed to the portion was inserted into the connection portion of the conductor connector embedded in the cold shrinkable insulator, and the conductor connector and the cable conductor were connected via the connection terminal. Thereafter, the expanded tube is pulled out from the inside of the insertion hole, and the portion of the insertion hole is elastically contracted with a part of the cold-shrinkable insulator, and the inner peripheral surface of the insertion hole is a cable constituting the power cable. Outer end of insulator A method of assembling a power cable connecting portion using a cold-shrinkable insulator that is in close contact with a power cable. 4. A power cable using a room-temperature shrinkable insulator according to claim 3, wherein the enlarged diameter tube is inclined at least in such a direction that its outer diameter becomes smaller as its distal end portion approaches the distal end edge. How to assemble the connection.